Polyconic Projection

A pseudoconical projection that is neither conformal nor equal area.
Often called the American Polyconic in Europe. The central meridian and
Equator are straight lines. All other meridians are complex curves.

Scale

True to scale along the central meridian. Each parallel is true to scale.

Distortion

Free of distortion along the central meridian and near the central meridian
distortion is very small.

Usage

Used almost exclusively in slightly modified form for large-scale mapping
in the United States until the 1950's.

Limitations

Normally used only for a single hemisphere.

Origin

Ferdinand Rudolph Hassler (1770 - 1843)

Hassler was born in Switzerland in 1770, arrived in the US in 1805,
taught mathematics at West Point and became the first Superintendent of
the U.S. Coast Survey, later heading the Bureau of Weights and Measures.
Hassler died in Philadelphia in 1843 as result of exposure after a fall
while trying to save his instruments in a severe wind and hail storm.